Blender Freestyle Brushes
Try using latest Blender 2.71 where you can specify your own brush texture image.  The Freestyle section of the Blender 2.71 release notes will be a useful information source about textured strokes.

http://wiki.blender.org/index.php/Dev:Ref/Release_Notes/2.71/Freestyle

There are two types of brush texture images: textures with and without tips.  Textures with tips need to be prepared in a specific arrangement of brush parts.  See the info graphics below which shows you what textures with tips look like.

http://blendernpr.org/freestyle-new-features-info-graphics/

I personally have never seen the Blender version in the screen capture of your post, although I am the main developer of Freestyle for Blender (: